[PATCH] - small cleanups to asm constraints

[John Baldwin]

Can you please test the patch below.  It makes use of the + modifier for a 
register variable in one place and fixes the asm constraints for _swp() to 
specify that _swp() modifies the memory being modified, not just the address 
of the memory (which isn't actually modified at that).  Note that this means 
that the generic "memory" clobber can probably be removed, but I haven't done 
that yet:

--- //depot/vendor/freebsd/src/sys/arm/include/atomic.h	2005/07/15 18:20:34
+++ //depot/projects/smpng/sys/arm/include/atomic.h	2005/07/18 17:20:49
@@ -77,8 +77,10 @@
 static __inline uint32_t
 __swp(uint32_t val, volatile uint32_t *ptr)
 {
-	__asm __volatile("swp	%0, %1, [%2]"
-	    : "=&r" (val) : "r" (val) , "r" (ptr) : "memory");
+	__asm __volatile("swp	%0, %2, [%3]"
+	    : "=&r" (val), "=m" (*ptr)
+	    : "r" (val) , "r" (ptr), "m" (*ptr)
+	    : "memory");
 	return (val);
 }
 
--- //depot/vendor/freebsd/src/sys/arm/include/endian.h	2005/05/24 21:45:17
+++ //depot/projects/smpng/sys/arm/include/endian.h	2005/07/18 17:20:49
@@ -100,11 +100,10 @@
 __bswap16_var(__uint16_t v)
 {
 	__asm __volatile(
-	    "mov    %0, %1, ror #8\n"
+	    "mov    %0, %0, ror #8\n"
 	    "orr    %0, %0, %0, lsr #16\n"
 	    "bic    %0, %0, %0, lsl #16"
-	    : "=r" (v)
-	    : "0" (v));
+	    : "+r" (v));
 	
 	return (v);
 }		

-- 
John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org